6PBJ

The structure of 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase with Gly190Pro mutation

Summary for 6PBJ

• Entry DOI: 10.2210/pdb6pbj/pdb
• Descriptor: Phospho-2-dehydro-3-deoxyheptonate aldolase, PHOSPHATE ION, SULFATE ION, ... (8 entities in total)
• Functional Keywords: dah7ps, allostery, shipmate pathway, tim barrel, transferase
• Biological source: Mycobacterium tuberculosis
• Total number of polymer chains: 2
• Total formula weight: 103444.53

Authors

Jiao, W.,Fan, Y.,Blackmore, N.J.,Parker, E.J. (deposition date: 2019-06-13, release date: 2020-04-08, Last modification date: 2023-10-11)

Primary citation

Jiao, W.,Fan, Y.,Blackmore, N.J.,Parker, E.J.
A single amino acid substitution uncouples catalysis and allostery in an essential biosynthetic enzyme in Mycobacterium tuberculosis .
J.Biol.Chem., 295:6252-6262, 2020

PubMed Abstract: Allostery exploits the conformational dynamics of enzymes by triggering a shift in population ensembles toward functionally distinct conformational or dynamic states. Allostery extensively regulates the activities of key enzymes within biosynthetic pathways to meet metabolic demand for their end products. Here, we have examined a critical enzyme, 3-deoxy-d--heptulosonate 7-phosphate synthase (DAH7PS), at the gateway to aromatic amino acid biosynthesis in , which shows extremely complex dynamic allostery: three distinct aromatic amino acids jointly communicate occupancy to the active site via subtle changes in dynamics, enabling exquisite fine-tuning of delivery of these essential metabolites. Furthermore, this allosteric mechanism is co-opted by pathway branchpoint enzyme chorismate mutase upon complex formation. In this study, using statistical coupling analysis, site-directed mutagenesis, isothermal calorimetry, small-angle X-ray scattering, and X-ray crystallography analyses, we have pinpointed a critical node within the complex dynamic communication network responsible for this sophisticated allosteric machinery. Through a facile Gly to Pro substitution, we have altered backbone dynamics, completely severing the allosteric signal yet remarkably, generating a nonallosteric enzyme that retains full catalytic activity. We also identified a second residue of prime importance to the inter-enzyme communication with chorismate mutase. Our results reveal that highly complex dynamic allostery is surprisingly vulnerable and provide further insights into the intimate link between catalysis and allostery.

PubMed: 32217694
DOI: 10.1074/jbc.RA120.012605

Experimental method

X-RAY DIFFRACTION (1.9 Å)